The invention pertains to optical connection and particularly to optical connectors making use of flexible connectors. More specifically, this invention pertains to the use of self-aligned, flexible optical connectors for coupling light between an optoelectronic device and an optical fiber, waveguide, or arrays of devices, fibers, and/or waveguides and a method of manufacture thereof.
A common problem is to simultaneously provide electrical connection to an optoelectronic device as well as optical coupling from the device to an optical fiber in a connected package. Previous methods of such coupling have included placing the device in a first level package, such as a TO header in an optical connector receptacle, rather than placing the device directly on the circuit board providing an electrical connection from the circuit board to the TO header by means of an electrical flex circuit. This approach involves costly and time consuming methods of manufacturing.
U.S. Pat. No. 5,375,184 (""184 patent) by inventor Charles T. Sullivan and issued Dec. 20, 1994, hereby incorporated by reference in this specification, appears to disclose 1) self-aligning mechanical approach for lateral waveguide to lateral waveguide alignment; 2) the use of visual alignment marks for lateral waveguide to lateral waveguide alignment or the alignment of a vertical port to a waveguide with a 45 degree facet; and 3) a coupling approach having alignment, but not for vertically coupled optical ports such as photodetectors, vertical cavity surface emitting lasers (VCSELs), or surface emitting light emitting diodes (LEDs). The alignment marks of the ""184 patent for use with a vertically coupled optical port still require manual alignment which is not self-aligning. This patent also does not deal with the approach for coupling between a flexible optical waveguide and an optical fiber waveguide within the connector receptacle.
The present invention has self-aligning features for waveguide self-alignment to a vertically coupled optical port such as a photodetector, VCSEL, or surface emitting LED. The invention also includes self-aligning or passively aligned structures for connector receptacles and backplanes. While the optical devices or optoelectronic integrated circuits are still at the wafer level, the wafer is coated and photolithographically patterned to provide the self-aligning features. Specifically, a pillar of dielectric or polymer material on the photodetector or laser wafer is fabricated in a fashion such that it fits or snaps into a recess of the waveguide thus providing a passive alignment with an accuracy of better than 5 micrometers (xcexcm). The added feature of this is the holding of the waveguide in place after the aligning fixtures are removed.
The features of the present invention include a self-aligning approach for coupling a waveguide or a plurality of waveguides to a vertically coupled device or devices, which can then be mounted directly onto a circuit board with other chips, without a first level package, and for connecting the other ends of the waveguides or connectors into optical connector receptacles of a module or a backplane.
The features of this approach include an optical waveguide or array of waveguides, that optically connect an optical device or devices at one end to a connector/connector receptacle at the other end. Self-aligning mechanical features provide 1 to 5 xcexcm alignment tolerances at the optical chip, while mechanical or visual alignment marks allow accurate placement of the waveguide in the connector receptacle at the other end, allowing automatic alignment to take place with machine vision.